Prometeusz (księżyc)

Prometeusz
Ilustracja
Zdjęcie Prometeusza oświetlonego światłem odbitym od Saturna, wykonane przez sondę Cassini (27 stycznia 2010)
Planeta

Saturn

Odkrywca

Stewart A. Collins
i D. Carlson (Voyager Science Team)

Data odkrycia

25 października 1980

Tymczasowe oznaczenie

S/1980 S27

Charakterystyka orbity
Półoś wielka

139 429 km[1]

Mimośród

0,0022[1]

Okres obiegu

0,613 d[1]

Nachylenie do płaszczyzny Laplace’a

0,007°[1]

Długość węzła wstępującego

319,176°[1]

Argument perycentrum

37,514°[1]

Anomalia średnia

96,886°[1]

Własności fizyczne
Wymiary

135,6 × 79,4 × 59,4 km[2]

Powierzchnia

~23 000 km²

Objętość

~340 000 km³

Masa

(1,595 ± 0,015) × 1017 kg[2]

Średnia gęstość

(0,48 ± 0,09) g/cm³[2]

Przyspieszenie grawitacyjne na powierzchni

0,0013–0,0058 m/s²[2]

Prędkość ucieczki

19 m/s

Okres obrotu wokół własnej osi

synchroniczny

Albedo

0,6

Jasność obserwowana
(z Ziemi)

15,5m

Temperatura powierzchni

74 K

Prometeusz (Saturn XVI) – jeden z wewnętrznych księżyców Saturna, odkryty w 1980 na podstawie zdjęć przesłanych przez sondę Voyager 1. Nazwa pochodzi od Prometeusza, postaci z mitologii greckiej.

Prometeusz przyciągający materię z pierścienia F

Prometeusz od wewnętrznej strony pierścienia F, wraz z Epimeteuszem i Janusem po zewnętrznej stronie, są księżycami pasterskimi tego pierścienia. Sonda Cassini zaobserwowała skomplikowane oddziaływanie między pierścieniem a Prometeuszem, którego grawitacja tworzy zagęszczenia, zafalowania, a czasem wręcz skręca pierścień F, a także przyciąga część materiału z niego.

Gęstość Prometeusza jest bardzo niska, jest to prawdopodobnie porowate, lodowe ciało[3].

Zobacz też

Przypisy

  1. a b c d e f g Planetary Satellite Mean Orbital Parameters. Jet Propulsion Laboratory, 2013-08-23. [dostęp 2016-02-21]. (ang.).
  2. a b c d P.C. Thomas. Sizes, shapes, and derived properties of the saturnian satellites after the Cassini nominal mission. „Icarus”. 208 (1), s. 395-401, lipiec 2010. DOI: 10.1016/j.icarus.2010.01.025. (ang.). 
  3. Prometheus. [w:] Solar System Exploration [on-line]. NASA. [dostęp 2018-12-26]. (ang.).

Linki zewnętrzne

Media użyte na tej stronie

Solar System XXX.png
This is a revised version of Solar_System_XXIX.png.
Saturn PIA06077.jpg
Saturn Cassini-Huygens (NASA)

Instrument: Imaging Science Subsystem - Narrow Angle

Saturn's peaceful beauty invites the Cassini spacecraft for a closer look in this natural color view, taken during the spacecraft's approach to the planet. By this point in the approach sequence, Saturn was large enough that two narrow angle camera images were required to capture an end-to-end view of the planet, its delicate rings and several of its icy moons. The composite is made entire from these two images.

Moons visible in this mosaic: Epimetheus (116 kilometers, 72 miles across), Pandora (84 kilometers, 52 miles across) and Mimas (398 kilometers, 247 miles across) at left of Saturn; Prometheus (102 kilometers, 63 miles across), Janus (181 kilometers, 113 miles across) and Enceladus (499 kilometers, 310 miles across) at right of Saturn.

The images were taken on May 7, 2004 from a distance of 28.2 million kilometers (17.6 million miles) from Saturn. The image scale is 169 kilometers (105 miles) per pixel. Moons in the image have been brightened for visibility.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras, were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information, about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.
Prometheus's effect on the F Ring.jpg

Prometheus causing kinks in Saturn's F Ring.

Full caption released with image:

As it completed its first orbit of Saturn, Cassini zoomed in on the rings to catch this wondrous view of the en:shepherd moon Prometheus (102 kilometers, or 63 miles across) working its influence on the multi-stranded and kinked F ring.

The F ring resolves into five separate strands in this closeup view. Potato-shaped Prometheus is seen here, connected to the ringlets by a faint strand of material. Imaging scientists are not sure exactly how Prometheus is interacting with the F ring here, but they have speculated that the moon might be gravitationally pulling material away from the ring. The ringlets are disturbed in several other places. In some, discontinuities or "kinks" in the ringlets are seen; in others, gaps in the diffuse inner strands are seen. All these features appear to be due to the influence of Prometheus.

The image was taken in visible light with the narrow angle camera on October 29, 2004, at a distance of about 782,000 kilometers (486,000 miles) from Prometheus and at a Sun-Prometheus-spacecraft, or phase, angle of 147 degrees. The image scale is 4.7 kilometers (2.9 miles) per pixel. The image has been magnified by a factor of two, and contrast was enhanced, to aid visibility.
PIA12593 Prometheus2.jpg
Cassini spacecraft image of Prometheus, one of Saturn's small inner moons. Appearing like eyes on a potato, craters cover the dimly lit surface of the moon Prometheus in this high-resolution image from Cassini's early 2010 flyby.

The Jan. 27 encounter represented the closest imaging sequence yet of that moon for Cassini. This view looks toward the trailing hemisphere of Prometheus (86 kilometers, 53 miles across). North on Prometheus is up and rotated 8 degrees to the right.

The moon is lit by sunlight on the right and Saturnshine on the left.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 27, 2010. The view was obtained at a distance of approximately 34,000 kilometers (21,000 miles) from Prometheus and at a Sun-Prometheus-spacecraft, or phase, angle of 126 degrees. Image scale is 200 meters (658 feet) per pixel.

The Cassini Equinox Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini Equinox Mission visit http://ciclops.org, http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

The original NASA image has been modified by cropping and brightening shadows. A version in which shadows are brightened less is here.